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-rw-r--r--drivers/pwm/pwm-meson.c386
1 files changed, 182 insertions, 204 deletions
diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
index fb5a369b1a8d..3cbff5cbb789 100644
--- a/drivers/pwm/pwm-meson.c
+++ b/drivers/pwm/pwm-meson.c
@@ -1,65 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
- * This file is provided under a dual BSD/GPLv2 license. When using or
- * redistributing this file, you may do so under either license.
+ * PWM controller driver for Amlogic Meson SoCs.
*
- * GPL LICENSE SUMMARY
+ * This PWM is only a set of Gates, Dividers and Counters:
+ * PWM output is achieved by calculating a clock that permits calculating
+ * two periods (low and high). The counter then has to be set to switch after
+ * N cycles for the first half period.
+ * The hardware has no "polarity" setting. This driver reverses the period
+ * cycles (the low length is inverted with the high length) for
+ * PWM_POLARITY_INVERSED. This means that .get_state cannot read the polarity
+ * from the hardware.
+ * Setting the duty cycle will disable and re-enable the PWM output.
+ * Disabling the PWM stops the output immediately (without waiting for the
+ * current period to complete first).
*
- * Copyright (c) 2016 BayLibre, SAS.
- * Author: Neil Armstrong <narmstrong@baylibre.com>
- * Copyright (C) 2014 Amlogic, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
- * The full GNU General Public License is included in this distribution
- * in the file called COPYING.
- *
- * BSD LICENSE
+ * The public S912 (GXM) datasheet contains some documentation for this PWM
+ * controller starting on page 543:
+ * https://dl.khadas.com/Hardware/VIM2/Datasheet/S912_Datasheet_V0.220170314publicversion-Wesion.pdf
+ * An updated version of this IP block is found in S922X (G12B) SoCs. The
+ * datasheet contains the description for this IP block revision starting at
+ * page 1084:
+ * https://dn.odroid.com/S922X/ODROID-N2/Datasheet/S922X_Public_Datasheet_V0.2.pdf
*
* Copyright (c) 2016 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@baylibre.com>
* Copyright (C) 2014 Amlogic, Inc.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * * Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- * * Neither the name of Intel Corporation nor the names of its
- * contributors may be used to endorse or promote products derived
- * from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+#include <linux/bitfield.h>
+#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
+#include <linux/math64.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
@@ -70,7 +45,8 @@
#define REG_PWM_A 0x0
#define REG_PWM_B 0x4
-#define PWM_HIGH_SHIFT 16
+#define PWM_LOW_MASK GENMASK(15, 0)
+#define PWM_HIGH_MASK GENMASK(31, 16)
#define REG_MISC_AB 0x8
#define MISC_B_CLK_EN BIT(23)
@@ -80,13 +56,33 @@
#define MISC_A_CLK_DIV_SHIFT 8
#define MISC_B_CLK_SEL_SHIFT 6
#define MISC_A_CLK_SEL_SHIFT 4
-#define MISC_CLK_SEL_WIDTH 2
+#define MISC_CLK_SEL_MASK 0x3
#define MISC_B_EN BIT(1)
#define MISC_A_EN BIT(0)
-static const unsigned int mux_reg_shifts[] = {
- MISC_A_CLK_SEL_SHIFT,
- MISC_B_CLK_SEL_SHIFT
+#define MESON_NUM_PWMS 2
+
+static struct meson_pwm_channel_data {
+ u8 reg_offset;
+ u8 clk_sel_shift;
+ u8 clk_div_shift;
+ u32 clk_en_mask;
+ u32 pwm_en_mask;
+} meson_pwm_per_channel_data[MESON_NUM_PWMS] = {
+ {
+ .reg_offset = REG_PWM_A,
+ .clk_sel_shift = MISC_A_CLK_SEL_SHIFT,
+ .clk_div_shift = MISC_A_CLK_DIV_SHIFT,
+ .clk_en_mask = MISC_A_CLK_EN,
+ .pwm_en_mask = MISC_A_EN,
+ },
+ {
+ .reg_offset = REG_PWM_B,
+ .clk_sel_shift = MISC_B_CLK_SEL_SHIFT,
+ .clk_div_shift = MISC_B_CLK_DIV_SHIFT,
+ .clk_en_mask = MISC_B_CLK_EN,
+ .pwm_en_mask = MISC_B_EN,
+ }
};
struct meson_pwm_channel {
@@ -94,8 +90,6 @@ struct meson_pwm_channel {
unsigned int lo;
u8 pre_div;
- struct pwm_state state;
-
struct clk *clk_parent;
struct clk_mux mux;
struct clk *clk;
@@ -109,8 +103,8 @@ struct meson_pwm_data {
struct meson_pwm {
struct pwm_chip chip;
const struct meson_pwm_data *data;
+ struct meson_pwm_channel channels[MESON_NUM_PWMS];
void __iomem *base;
- u8 inverter_mask;
/*
* Protects register (write) access to the REG_MISC_AB register
* that is shared between the two PWMs.
@@ -125,12 +119,16 @@ static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
- struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
+ struct meson_pwm *meson = to_meson_pwm(chip);
+ struct meson_pwm_channel *channel;
struct device *dev = chip->dev;
int err;
- if (!channel)
- return -ENODEV;
+ channel = pwm_get_chip_data(pwm);
+ if (channel)
+ return 0;
+
+ channel = &meson->channels[pwm->hwpwm];
if (channel->clk_parent) {
err = clk_set_parent(channel->clk, channel->clk_parent);
@@ -149,9 +147,7 @@ static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
return err;
}
- chip->ops->get_state(chip, pwm, &channel->state);
-
- return 0;
+ return pwm_set_chip_data(pwm, channel);
}
static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
@@ -162,20 +158,18 @@ static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
clk_disable_unprepare(channel->clk);
}
-static int meson_pwm_calc(struct meson_pwm *meson,
- struct meson_pwm_channel *channel, unsigned int id,
- unsigned int duty, unsigned int period)
+static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm,
+ struct pwm_state *state)
{
- unsigned int pre_div, cnt, duty_cnt;
+ struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
+ unsigned int duty, period, pre_div, cnt, duty_cnt;
unsigned long fin_freq = -1;
- u64 fin_ps;
- if (~(meson->inverter_mask >> id) & 0x1)
- duty = period - duty;
+ duty = state->duty_cycle;
+ period = state->period;
- if (period == channel->state.period &&
- duty == channel->state.duty_cycle)
- return 0;
+ if (state->polarity == PWM_POLARITY_INVERSED)
+ duty = period - duty;
fin_freq = clk_get_rate(channel->clk);
if (fin_freq == 0) {
@@ -184,24 +178,19 @@ static int meson_pwm_calc(struct meson_pwm *meson,
}
dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
- fin_ps = (u64)NSEC_PER_SEC * 1000;
- do_div(fin_ps, fin_freq);
-
- /* Calc pre_div with the period */
- for (pre_div = 0; pre_div <= MISC_CLK_DIV_MASK; pre_div++) {
- cnt = DIV_ROUND_CLOSEST_ULL((u64)period * 1000,
- fin_ps * (pre_div + 1));
- dev_dbg(meson->chip.dev, "fin_ps=%llu pre_div=%u cnt=%u\n",
- fin_ps, pre_div, cnt);
- if (cnt <= 0xffff)
- break;
- }
+ pre_div = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * 0xffffLL);
if (pre_div > MISC_CLK_DIV_MASK) {
dev_err(meson->chip.dev, "unable to get period pre_div\n");
return -EINVAL;
}
+ cnt = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * (pre_div + 1));
+ if (cnt > 0xffff) {
+ dev_err(meson->chip.dev, "unable to get period cnt\n");
+ return -EINVAL;
+ }
+
dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", period,
pre_div, cnt);
@@ -215,8 +204,8 @@ static int meson_pwm_calc(struct meson_pwm *meson,
channel->lo = cnt;
} else {
/* Then check is we can have the duty with the same pre_div */
- duty_cnt = DIV_ROUND_CLOSEST_ULL((u64)duty * 1000,
- fin_ps * (pre_div + 1));
+ duty_cnt = div64_u64(fin_freq * (u64)duty,
+ NSEC_PER_SEC * (pre_div + 1));
if (duty_cnt > 0xffff) {
dev_err(meson->chip.dev, "unable to get duty cycle\n");
return -EINVAL;
@@ -233,73 +222,43 @@ static int meson_pwm_calc(struct meson_pwm *meson,
return 0;
}
-static void meson_pwm_enable(struct meson_pwm *meson,
- struct meson_pwm_channel *channel,
- unsigned int id)
+static void meson_pwm_enable(struct meson_pwm *meson, struct pwm_device *pwm)
{
- u32 value, clk_shift, clk_enable, enable;
- unsigned int offset;
+ struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
+ struct meson_pwm_channel_data *channel_data;
unsigned long flags;
+ u32 value;
- switch (id) {
- case 0:
- clk_shift = MISC_A_CLK_DIV_SHIFT;
- clk_enable = MISC_A_CLK_EN;
- enable = MISC_A_EN;
- offset = REG_PWM_A;
- break;
-
- case 1:
- clk_shift = MISC_B_CLK_DIV_SHIFT;
- clk_enable = MISC_B_CLK_EN;
- enable = MISC_B_EN;
- offset = REG_PWM_B;
- break;
-
- default:
- return;
- }
+ channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];
spin_lock_irqsave(&meson->lock, flags);
value = readl(meson->base + REG_MISC_AB);
- value &= ~(MISC_CLK_DIV_MASK << clk_shift);
- value |= channel->pre_div << clk_shift;
- value |= clk_enable;
+ value &= ~(MISC_CLK_DIV_MASK << channel_data->clk_div_shift);
+ value |= channel->pre_div << channel_data->clk_div_shift;
+ value |= channel_data->clk_en_mask;
writel(value, meson->base + REG_MISC_AB);
- value = (channel->hi << PWM_HIGH_SHIFT) | channel->lo;
- writel(value, meson->base + offset);
+ value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) |
+ FIELD_PREP(PWM_LOW_MASK, channel->lo);
+ writel(value, meson->base + channel_data->reg_offset);
value = readl(meson->base + REG_MISC_AB);
- value |= enable;
+ value |= channel_data->pwm_en_mask;
writel(value, meson->base + REG_MISC_AB);
spin_unlock_irqrestore(&meson->lock, flags);
}
-static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
+static void meson_pwm_disable(struct meson_pwm *meson, struct pwm_device *pwm)
{
- u32 value, enable;
unsigned long flags;
-
- switch (id) {
- case 0:
- enable = MISC_A_EN;
- break;
-
- case 1:
- enable = MISC_B_EN;
- break;
-
- default:
- return;
- }
+ u32 value;
spin_lock_irqsave(&meson->lock, flags);
value = readl(meson->base + REG_MISC_AB);
- value &= ~enable;
+ value &= ~meson_pwm_per_channel_data[pwm->hwpwm].pwm_en_mask;
writel(value, meson->base + REG_MISC_AB);
spin_unlock_irqrestore(&meson->lock, flags);
@@ -316,64 +275,97 @@ static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
return -EINVAL;
if (!state->enabled) {
- meson_pwm_disable(meson, pwm->hwpwm);
- channel->state.enabled = false;
-
- return 0;
- }
-
- if (state->period != channel->state.period ||
- state->duty_cycle != channel->state.duty_cycle ||
- state->polarity != channel->state.polarity) {
- if (state->polarity != channel->state.polarity) {
- if (state->polarity == PWM_POLARITY_NORMAL)
- meson->inverter_mask |= BIT(pwm->hwpwm);
- else
- meson->inverter_mask &= ~BIT(pwm->hwpwm);
+ if (state->polarity == PWM_POLARITY_INVERSED) {
+ /*
+ * This IP block revision doesn't have an "always high"
+ * setting which we can use for "inverted disabled".
+ * Instead we achieve this using the same settings
+ * that we use a pre_div of 0 (to get the shortest
+ * possible duration for one "count") and
+ * "period == duty_cycle". This results in a signal
+ * which is LOW for one "count", while being HIGH for
+ * the rest of the (so the signal is HIGH for slightly
+ * less than 100% of the period, but this is the best
+ * we can achieve).
+ */
+ channel->pre_div = 0;
+ channel->hi = ~0;
+ channel->lo = 0;
+
+ meson_pwm_enable(meson, pwm);
+ } else {
+ meson_pwm_disable(meson, pwm);
}
-
- err = meson_pwm_calc(meson, channel, pwm->hwpwm,
- state->duty_cycle, state->period);
+ } else {
+ err = meson_pwm_calc(meson, pwm, state);
if (err < 0)
return err;
- channel->state.polarity = state->polarity;
- channel->state.period = state->period;
- channel->state.duty_cycle = state->duty_cycle;
- }
-
- if (state->enabled && !channel->state.enabled) {
- meson_pwm_enable(meson, channel, pwm->hwpwm);
- channel->state.enabled = true;
+ meson_pwm_enable(meson, pwm);
}
return 0;
}
+static unsigned int meson_pwm_cnt_to_ns(struct pwm_chip *chip,
+ struct pwm_device *pwm, u32 cnt)
+{
+ struct meson_pwm *meson = to_meson_pwm(chip);
+ struct meson_pwm_channel *channel;
+ unsigned long fin_freq;
+ u32 fin_ns;
+
+ /* to_meson_pwm() can only be used after .get_state() is called */
+ channel = &meson->channels[pwm->hwpwm];
+
+ fin_freq = clk_get_rate(channel->clk);
+ if (fin_freq == 0)
+ return 0;
+
+ fin_ns = div_u64(NSEC_PER_SEC, fin_freq);
+
+ return cnt * fin_ns * (channel->pre_div + 1);
+}
+
static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct meson_pwm *meson = to_meson_pwm(chip);
- u32 value, mask;
+ struct meson_pwm_channel_data *channel_data;
+ struct meson_pwm_channel *channel;
+ u32 value, tmp;
if (!state)
return;
- switch (pwm->hwpwm) {
- case 0:
- mask = MISC_A_EN;
- break;
+ channel = &meson->channels[pwm->hwpwm];
+ channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];
- case 1:
- mask = MISC_B_EN;
- break;
+ value = readl(meson->base + REG_MISC_AB);
- default:
- return;
- }
+ tmp = channel_data->pwm_en_mask | channel_data->clk_en_mask;
+ state->enabled = (value & tmp) == tmp;
- value = readl(meson->base + REG_MISC_AB);
- state->enabled = (value & mask) != 0;
+ tmp = value >> channel_data->clk_div_shift;
+ channel->pre_div = FIELD_GET(MISC_CLK_DIV_MASK, tmp);
+
+ value = readl(meson->base + channel_data->reg_offset);
+
+ channel->lo = FIELD_GET(PWM_LOW_MASK, value);
+ channel->hi = FIELD_GET(PWM_HIGH_MASK, value);
+
+ if (channel->lo == 0) {
+ state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->hi);
+ state->duty_cycle = state->period;
+ } else if (channel->lo >= channel->hi) {
+ state->period = meson_pwm_cnt_to_ns(chip, pwm,
+ channel->lo + channel->hi);
+ state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm,
+ channel->hi);
+ } else {
+ state->period = 0;
+ state->duty_cycle = 0;
+ }
}
static const struct pwm_ops meson_pwm_ops = {
@@ -433,8 +425,17 @@ static const struct meson_pwm_data pwm_axg_ao_data = {
.num_parents = ARRAY_SIZE(pwm_axg_ao_parent_names),
};
+static const char * const pwm_g12a_ao_ab_parent_names[] = {
+ "xtal", "aoclk81", "fclk_div4", "fclk_div5"
+};
+
+static const struct meson_pwm_data pwm_g12a_ao_ab_data = {
+ .parent_names = pwm_g12a_ao_ab_parent_names,
+ .num_parents = ARRAY_SIZE(pwm_g12a_ao_ab_parent_names),
+};
+
static const char * const pwm_g12a_ao_cd_parent_names[] = {
- "aoclk81", "xtal",
+ "xtal", "aoclk81",
};
static const struct meson_pwm_data pwm_g12a_ao_cd_data = {
@@ -478,7 +479,7 @@ static const struct of_device_id meson_pwm_matches[] = {
},
{
.compatible = "amlogic,meson-g12a-ao-pwm-ab",
- .data = &pwm_axg_ao_data
+ .data = &pwm_g12a_ao_ab_data
},
{
.compatible = "amlogic,meson-g12a-ao-pwm-cd",
@@ -488,8 +489,7 @@ static const struct of_device_id meson_pwm_matches[] = {
};
MODULE_DEVICE_TABLE(of, meson_pwm_matches);
-static int meson_pwm_init_channels(struct meson_pwm *meson,
- struct meson_pwm_channel *channels)
+static int meson_pwm_init_channels(struct meson_pwm *meson)
{
struct device *dev = meson->chip.dev;
struct clk_init_data init;
@@ -498,7 +498,7 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
int err;
for (i = 0; i < meson->chip.npwm; i++) {
- struct meson_pwm_channel *channel = &channels[i];
+ struct meson_pwm_channel *channel = &meson->channels[i];
snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i);
@@ -509,8 +509,9 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
init.num_parents = meson->data->num_parents;
channel->mux.reg = meson->base + REG_MISC_AB;
- channel->mux.shift = mux_reg_shifts[i];
- channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
+ channel->mux.shift =
+ meson_pwm_per_channel_data[i].clk_sel_shift;
+ channel->mux.mask = MISC_CLK_SEL_MASK;
channel->mux.flags = 0;
channel->mux.lock = &meson->lock;
channel->mux.table = NULL;
@@ -525,31 +526,16 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
snprintf(name, sizeof(name), "clkin%u", i);
- channel->clk_parent = devm_clk_get(dev, name);
- if (IS_ERR(channel->clk_parent)) {
- err = PTR_ERR(channel->clk_parent);
- if (err == -EPROBE_DEFER)
- return err;
-
- channel->clk_parent = NULL;
- }
+ channel->clk_parent = devm_clk_get_optional(dev, name);
+ if (IS_ERR(channel->clk_parent))
+ return PTR_ERR(channel->clk_parent);
}
return 0;
}
-static void meson_pwm_add_channels(struct meson_pwm *meson,
- struct meson_pwm_channel *channels)
-{
- unsigned int i;
-
- for (i = 0; i < meson->chip.npwm; i++)
- pwm_set_chip_data(&meson->chip.pwms[i], &channels[i]);
-}
-
static int meson_pwm_probe(struct platform_device *pdev)
{
- struct meson_pwm_channel *channels;
struct meson_pwm *meson;
struct resource *regs;
int err;
@@ -567,19 +553,13 @@ static int meson_pwm_probe(struct platform_device *pdev)
meson->chip.dev = &pdev->dev;
meson->chip.ops = &meson_pwm_ops;
meson->chip.base = -1;
- meson->chip.npwm = 2;
+ meson->chip.npwm = MESON_NUM_PWMS;
meson->chip.of_xlate = of_pwm_xlate_with_flags;
meson->chip.of_pwm_n_cells = 3;
meson->data = of_device_get_match_data(&pdev->dev);
- meson->inverter_mask = BIT(meson->chip.npwm) - 1;
- channels = devm_kcalloc(&pdev->dev, meson->chip.npwm,
- sizeof(*channels), GFP_KERNEL);
- if (!channels)
- return -ENOMEM;
-
- err = meson_pwm_init_channels(meson, channels);
+ err = meson_pwm_init_channels(meson);
if (err < 0)
return err;
@@ -589,8 +569,6 @@ static int meson_pwm_probe(struct platform_device *pdev)
return err;
}
- meson_pwm_add_channels(meson, channels);
-
platform_set_drvdata(pdev, meson);
return 0;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-19 10:22:07 +0000